phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 144 Table './phpbb_1/phpbb_sessions' is marked as crashed and last (automatic?) repair failed

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('bc91f258e9a71270a8db6364d39a0f72', -1, 1425692169, 1425692169, '36a19e47', 13, 0)

Line : 158
File : /forum/includes/sessions.php